Circuit board assembly with pads and connection lines having same resistance value as the pads and impedance matching method

ABSTRACT

A circuit board assembly includes a circuit board, at least one pad formed on the circuit board, and at least one connection line. Each of the at least one connection line includes a connection end connected to a respective one of the at least one pad and has the same resistance value as the respective pad.

FIELD

The subject matter herein generally relates to a circuit board assembly and an impedance matching method for the circuit board assembly.

BACKGROUND

Wireless radio frequency transceiver technology as a new fiber-optic connector standard has been gradually applied to electronic products. Current radio frequency transceivers can reach the speed of the single-channel 10 Gb/s, in such a high-frequency transmission, impedance matching becomes particularly important. If there is an impedance mismatch, very large amounts of energy will be lost and the bit error rate increased, so the impedance matching design is very important in the wireless radio frequency transceiver. Existing technology is commonly used to change the circuit design of a high-frequency circuit to change the impedance, but in order to achieve the connected circuit impedance matching, the matching method is complicated.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present technology will now be described, by way of example only, with reference to the attached figures, wherein:

FIG. 1 is an assembled, plan view of a circuit board assembly which includes a circuit board, a number of pads, and a number of connection lines, according to a first exemplary embodiment.

FIG. 2 is a flowchart of an impedance matching method, according to a second exemplary embodiment.

FIG. 3 is an assembled, plan view of the circuit board and the number of pads of FIG. 1.

FIG. 4 is a cross-sectional view of the circuit board and one of the pads taken along line IV-IV.

FIG. 5 is a flowchart of an impedance matching method, according to a third exemplary embodiment.

FIG. 6 is a flowchart of an impedance matching method, according to a fourth exemplary embodiment.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the present disclosure.

Several definitions that apply throughout this disclosure will now be presented.

The term “substantially” is defined to be essentially conforming to the particular dimension, shape or other word that substantially modifies, such that the component need not be exact. For example, substantially cylindrical means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like.

The present disclosure is described in relation to a circuit board, the circuit board assembly comprises a circuit board, at least one pad positioned on the circuit board and at least one connection line, wherein each of the at least one connection line comprising a connection end connected to a respective one of the at least one pad and having the same resistance value as the respective pad.

FIG. 1 illustrates a circuit board assembly 100 according to a first exemplary embodiment. The circuit board assembly 100 includes a circuit board 10, a number of pads 20, and a number of connection lines 30. In the embodiment, the circuit board assembly 100 is used in a wireless radio frequency transceiver (not shown).

The circuit board 10 is substantially rectangular. The number of pads 20 are formed on one sidewall of the circuit board 10. It should be noted that, the circuit board 10 also can be other shapes, such as circular.

Each of the connection lines 30 includes a connection end 31. Each of the connection ends 31 is connected to a pad 20. In particular, a pad 20 and a connection line 30 connected to the pad 20 have the same resistance value.

One of the pads 20 and one of the connection lines 30 connected to the pad 20 of the circuit board assembly 100 have the same resistance value, as such, the circuit design for reaching an impedance matching, is made easier, with a significant improvement in circuit characteristics.

FIGS. 3 and 4 illustrate a flowchart of a method for impedance matching between a pad 20 and a connection line 30, according to a second exemplary embodiment.

Also referring to FIG. 2, The example method is provided by way of example, as there are a variety of ways to carry out the method. The method described below can be carried out using the configurations illustrated in FIG. 2 for example, and various elements of these figures are referenced in explaining example method. Blocks shown in FIG. 2 represents one or more processes, methods or subroutines, carried out in the exemplary method. Additionally, the illustrated order of blocks is by example only and the order of the blocks can change according to the present disclosure. The method includes the following blocks:

At block 101: forming the pad 20 on the circuit board 10, the pad 20 having a predetermined thickness and having a predetermined horizontal cross-sectional area. According to the formula: R=ρL/A, wherein R is the resistance value (unit is the ohm) of the pad 20; ρ is the resistivity of the pad 20 (unit is ohm·m); L is the thickness of the pad 20 (unit is m); A is the horizontal cross-sectional area of the pad 20 (unit is the square meter). As such, only by controlling the thickness and the horizontal cross-section area of the pad 20 does the pad 20 have a predetermined resistance value. In the embodiment, the resistance value of the pad 20 is 50 ohms.

At block 102: the connection line 30 is fabricated, the length is controlled and the horizontal cross-sectional area of the connection line 30 is controlled to create a connection line 30 having the same predetermined resistance value as the pad 20. According to the formula: R=ρL/A, wherein R is the resistance value of the connection line 30 (unit is the ohm); ρ is the resistivity of the connection line 30 (unit is ohm·m); L is the length of the connection line 30 (unit is m); A is the horizontal cross-sectional area of the connection line 30 (unit is the square meter). As such, only by controlling the length and the horizontal cross-sectional area of the connection line 30 is the creation of a connection line 30 allowed having the same predetermined resistance value as the pad 20.

At block 103: the connection end 31 of the connection line 30 is electrically connected to the pad 20.

Referring to FIG. 5, a flowchart of a method for impedance matching between a pad 20 and a connection line 30 is presented in accordance with an example embodiment which is being thus illustrated. The example method is provided by way of example, as there are a variety of ways to carry out the method. The method described below can be carried out using the configurations illustrated in FIG. 5 for example, and various elements of these figures are referenced in explaining example method. Blocks shown in FIG. 5 represents one or more processes, methods or subroutines, carried out in the exemplary method. Additionally, the illustrated order of blocks is by example only and the order of the blocks can change according to the present disclosure. The method includes the following blocks:

At block 201: a resistance value of the pad 20 is obtained via a multimeter; At block 202: the connection line 30 is fabricated, and the length and the horizontal cross-sectional area of the connection line 30 is controlled to create a connection line 30 having the same predetermined resistance value as the pad 20; At block 203: a connection end 31 of the connection line 30 to the pad 20 is electrically connected.

Referring to FIG. 6, a flowchart for impedance matching between a pad 20 and a connection line 30 is presented in accordance with an example embodiment which is being thus illustrated. The example method is provided by way of example, as there are a variety of ways to carry out the method. The method described below can be carried out using the configurations illustrated in FIG. 6, for example, and various elements of these figures are referenced in explaining example method. block shown in FIG. 6 represents one or more processes, methods or subroutines, carried out in the exemplary method. Additionally, the illustrated order of blocks is by example only and the order of the blocks can change according to the present disclosure. The method includes the following blocks:

At block 301: a resistance value of the connection line 30 is obtained via a multimeter; At block 302: the pad 20 on the circuit board 10 is formed, and the thickness and the horizontal cross-sectional area of the pad 20 is controlled to form a pad 20 having the same predetermined resistance value as the connection line 30; At block 303: a connection end 31 of the connection line 30 is electrically connected to the pad 20.

The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of a circuit board. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, especially in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims. 

What is claimed is:
 1. A circuit board assembly comprising: a circuit board; at least one pad positioned on the circuit board; and at least one connection line, wherein each of the at least one connection line comprising a connection end connected to a respective one of the at least one pad and having the same resistance value as the respective pad.
 2. The circuit board assembly of claim 1, wherein the resistance value of each pad is 50 ohm.
 3. An impedance matching method for impedance matching between a pad and a connection line, the method comprising: providing a circuit board and one of the pad and the connection line; obtaining a resistance value of the one of the pad and the connection line via a multimeter; fabricating the other one of the pad and the connection line, the pad and the connection line having the same resistance value; positioning the pad on the circuit board; and connecting a connection end of the connection line to the pad. 